Preventing the rising of leads in press-forms.



H. DANNENBERG.'

PREVENTING THE. RISING 0P LEADS IN PRESS FORMS. APPLIOATION FILED APR. '3, 1907.

905,293. Patented Dec. 1, 1908.

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UNITED strATEs r TENT OFFICE.

HER-MANN DANNENBEE G, OF LEIPZIG-SELLERI-IAUSEN, GERMANY, ASSIGNOR TO THE FIRM OF GEBRUDEB KLUG, OF DEHNITZ, NEAR WURZEN, GERMANY.

PREVENTING THE RISING or LEADS IN PRESS-FORMS.

Specification of Letters Patent.

Applicationfiled. April 3, 1907.

Patented Dec. 1, 1908.

Serial No. 366,201.

To all whom 'it may concern:

Be it known that I, HERMANN DANNEN- BERG, a subject of the King of Saxony, re-

siding in Leipzig- Sellerhausen, Saxony, have strips or blocks introduced between the letters to preserve their positions, it has been proposed to subject the under side of the press form to a hardening or stiffening material such for example as a solution of gum arabic, gelatin, or other sticky material soluble in water and solidifying at ordinary temperatures, orof varnish or the like, in such a way. that the sticky material enters the spaces between the letters and the leads; which sticky material after becoming stiff holds the separate parts of the press form in their positions. This process, experience shows, has the disadvantage that the oil which has heretofore been provided upon the foundation or backing plate or part of the machine upon which the press form bears during the printing or into which it is inserted, and which oil has been used for preventing rusting, has prevented to a large degree the operation of the sticky material applied, so that the rising of the leads has not been prevented. The sticky layer upon the under side of the press form is shifted by the introduction of the press form into the chase often altogether, so that also a portion of the oil is squeezed out and oil free spaces are formed at which the dry sticky material becomes so strongly fastened as to make impossible the removal of the press form without injury. Also the dried sticky material on the back readily separates in case the turpentine or similar washing fluid which is used for cleaning the form passes between the letters. 1

According to the present invention the backing plate is provided not with oil, but with a sticky mass. This may consist for example of resin lacquer, copal lacquer, colophony, copabia balsam Venetian turpentime, to which fat or a fatty oil is added, or of solutions of gum or gelatin to which glycerin is added. This material attaches itself at the contact points to the corresponding sticky coating upon the under side of the press form, so that the latter is protected before complete hardening in such a way as to completely prevent its separation by the cleaning of the press form. It is not squeezed out, since it does not form a slippery coating like oil, but forms a toughly elastic coating upon the backing plate, so that a rising of the leads is securely prevented. This sticky material can also be laid upon an intermediate plate which is to be laid upon the chase or backing, and upon which the press form is to be laid. In this case the intermediate plate constitutes the real surface of the backing plate.

The mass applied on the backing (as well as the sticky mass applied to the back of the press form) needs only to be very thinly laid on, since a thin coating is quite sufficient to prevent the rising of the leads. Such a coating may be very evenly laid on, which is not true of a heavy coating. Thus I obtain the further advantages that material is saved, the press form is uniformly coated all over, and that no material is pressed out.

The accompanying drawing illustrates the process, the figure showing a section of a form of set types.

In the drawing the sticky mass A is applied to the under face of the press form A, and B is a sheet of the same mass applied to the backing C.

I claim as my invention 1- 1. Method of preventing the rising of leads in press forms which consists in pasting the under surface of the press form to its backing by coating the backing with a sticky material, coating the under face of the press form with a sticky material and applying the press form to the backing.

2. In the making up and backing of press forms, the method which consists in suitably arranging a number of separate types and leads, holding the same together temporasigned my name in the presence of two suhrlly, eoatlng the under face thereof wlth serlblng wltnesses. a stlcky mat-renal, eoatlng the backlng W1th a sticky material, and applying the types HEILMABA DABkLBJLM" 5 and leads to the backing to paste them; Vitnesses:

thereon.

EDWARD GijTzE, In wltness whereof, I have hereunto RUDOLPH Fmclm. 

